Tim Berners-Lee wrote
Making something like pub:name a subProperty of rdfs:label is
essential for the Tabulator for example to know it can use names as
labels in the UI. So please do it
Tim, please see my previous message on this. To your request, a while
ago we made a similar move in Geonames ontology, and have to define a
OWL-Full ontology importing the OWL-Lite ontology plus the subproperties
declarations. As said in my previous message I consider this as being a
suboptimal patch to the fact that the built-in OWL vocabulary does not
provide any proper way to define a hierachy of name types.
Would you recommend that SKOS vocabulary, for example, defines
skos:prefLabel and skos:altLabel as subproperties of rdfs:label in
order to make Tabulator and the like happy, and hence moving to OWl-Full?
(and don't duplicate the data in pub:name and rdfs:label in the data!)
Presumably OWL DL systems can be built to ignore the rdfs:subClassOf
fact when they do OWL-DL reasoning on the data.
Recommending systems built on the semantics of OWL, which are quite hard
to set up and define properly, to ignore parts of this very semantics
sounds to me as a strange recommendation coming from the very W3C top :-)
But : as said before, the real issue is that you ask both vocabulary
publishers and implementers to hack the standards semantics, default any
proper way in those standards to deal with names.
What I suggest here (with cc to SKOS forum) is to define somewhere a
standard generic label datatype property, which could be easily refined
in specific types of labels while keeping in OWL-DL; making everybody
happy. The most natural place to do that seems to be SKOS namespace.
Here is the proposal
skos:label a owl:DatatypeProperty
skos:prefLabel rdfs:subPropertyOf skos:label
skos:altLabel rdfs:subPropertyOf skos:label
...
pub:name rdfs:subPropertyOf skos:label
Applications and vocabularies wanting to stick to OWL-DL would use
skos:label and its extensive subproperties instead of rdfs:label
RDFS-only applications would just have to add
skos:label rdfs:subPropertyOf rdfs:label
What do people think?
Bernard
PS : just reading John's answer ... I guess he would be very happy with
such a solution
Tim
On 2008-07 -29, at 12:59, Richard Cyganiak wrote:
Bijan, Knud, Bernard, thanks for the clarification.
I'm indeed surprised! Subclassing rdfs:label is okay in RDFS, and it
is okay in OWL Full, but it is not allowed in OWL DL.
The RDF consumers I'm working on (RDF browsers and the Sindice
engine) don't care if you're in OWL DL or not, so I'm tempted to
argue that it doesn't matter much for RDF publishing on the Web.
(IME, on the open Web, trust and provenance are much larger issues
than inference, and I don't believe that the open Web will ever be
OWL DL, so why bother.)
Others here will probably have different perspectives on this question.
Richard
On 28 Jul 2008, at 17:01, Bijan Parsia wrote:
On 28 Jul 2008, at 16:23, Richard Cyganiak wrote:
On 28 Jul 2008, at 15:52, John Goodwin wrote:
In an ideal
world, John would declare pub:name a subproperty of
rdfs:label, and the tools would infer the rdfs:label value...
But most clients don't do that yet.
Am I allowed to declare something as subproperty of rdfs:label?
As far as I know, yes.
I'm
guessing this is one of those things that is allow in RDF, but not in
OWL DL?
I would be surprised if that is the case.
You're surprised.
What makes you think so?
The spec? :) But also you can try one of the species validators.
(rdfs:label is an annotation property and you are not allowed to
subproperty annotation properties in OWL DL)
http://www.w3.org/TR/owl-semantics/syntax.html#2.1
"""Properties relate individuals to other information, and are
divided into four disjoint groups, data-valued properties,
individual-valued properties, annotation properties, and ontology
properties"""
Then if you look at the rest of the grammar, you'll see where
annotation properties are allowed.
Can anyone else comment on this?
(FWIW, foaf:name is a subproperty of rdfs:label.)
And hence, not OWL DL.
Historywise, this sort of annotation is a kind of metamodeling. At
the time, the WebOnt working group (at least the DL contingent)
wasn't sure how to handle this (it's not a standard feature of
logics, esp. if you give it a strong semantic reading a la OWL
Full). So the compromise was to forbid this.
In OWL 2 (DL), you can get this sort of effect two ways, annotations
(which are under discussion and being explored) or by punning
classes and individuals (which won't actually help you with the
built in vocabulary).
Typically, subpropertying rdfs:label isn't really a *domain
modeling* thing, but an attempt to spec a *presentational* issue
(i.e., many UIs exploit rdfs:label, and one wants to indicate which
properties should show up in the UI). Thus, there's a bit of tension
there.
HTH.
Cheers,
Bijan.
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